Master brake cylinders having a vacuum-type brake force booster are known and are common for vehicle brake systems in passenger motor vehicles.
The laid-open specification DE 103 27 553 A1 discloses an electromechanical brake force booster having an electric motor which acts via a rotation/translation conversion mechanism on a thrust rod piston of a hydraulic master brake cylinder. The electric motor of the known brake force booster is a hollow-shaft motor, the hollow shaft of which is formed as a nut of a spindle gearing. The spindle gearing forms a rotation/translation conversion mechanism which converts the rotational drive movement of the electric motor into a translatory drive output movement for displacing the thrust rod piston. An electromechanical brake force booster may be of some other design. A thrust rod piston refers here to the or a piston of the master brake cylinder which, for the actuation of the master brake cylinder, is displaced in the master brake cylinder by the brake force booster and/or by the muscle force of a vehicle driver. The thrust rod piston may also be referred to as primary piston or simply as piston or master brake cylinder piston. The displacement of the thrust rod piston by muscle force, that is to say an actuation of the master brake cylinder under muscle force, is conventionally carried out with a foot by means of a (foot-operated) brake pedal or by hand by means of a (hand-operated) brake lever.